1. Field of the Invention
The present invention relates generally to bellows for removing debris from the cutting path of a saw and, more particularly, to a bellows with a flexible stem for use in a scroll saw.
2. Description of the Related Art
Scroll saws (or jig saws) typically comprise a saw blade connected between the free ends of two reciprocating arms. A frame supports the reciprocating arms and a work table positioned so that the saw blade passes through an opening in the work table. The reciprocating arms are attached to the frame by bearings that permit the arms to pivot, and a motor is linked to the reciprocating arms. In operation, the motor causes the arms to rapidly reciprocate about their pivots, causing the saw blade to move up and down rapidly. A scroll saw of this type is described in U.S. Pat. No. 5,197,369, which is hereby incorporated by reference.
During operation of the scroll saw, a workpiece is cut by placing the workpiece against the reciprocating saw blade and guiding the workpiece so that a cut of the desired shape is made. However, sawdust, metal filings, or other material removed from the workpiece by the saw blade can accumulate on the workpiece and hinder efficient operation of the scroll saw by blocking the operator's view, thereby preventing the user from accurately controlling the shape of the cut. The present invention provides an improved device and method for removing accumulated sawdust or other debris from the cutting path of a saw blade.
Bellows have been used in the past in scroll saws to blow air to remove sawdust from the cutting path of the saw blade. Bellows are suited for this application because the reciprocating movement of the scroll saw's arms can be conveniently used to repeatedly compress and release the bellows, generating the desired airflow.
Previous bellows designs have included a short, non-flexible nipple at one end of the bellows for connection to a flexible air hose that is used to direct the airflow in the desired direction. However, when such bellows are used in applications with space restrictions requiring the air hose to make a right-angle bend near to its point of attachment to the bellows, the vibration of the scroll saw tends to cause the air hose to work loose from the nipple. To solve this problem, some designs have included a separate rigid elbow-shaped tube with a right-angle bend that connects to the nipple on the bellows at one end and the air hose at the other end. This design requires the elbow to be manufactured as a separate piece from the bellows because the blow molding process typically used to make the bellows cannot be used to produce an angled nipple.
Another problem occurs when a blow molding process is used to produce the bellows from a plastic material. Although this method of manufacture is very economical, it often produces wall thickness irregularities in the article being manufactured. These irregularities occur in the area where the blow vent needle is located. Any irregularity in the wall thickness will create internal stresses in the plastic material when the area with the irregularity is flexed, leading to cracking of the wall. During operation of the bellows, the bellows section is repeatedly compressed and released, flexing the walls of the bellows section. Thus, any wall thickness irregularities in the bellows section increases the risk of premature failure of the part.